Why do Onions make you Cry?

Onions “make people cry”. Most assume it is simply because of their strong odor. This is not the case. Through research, it was discovered that the connection between onions and crying is actually much more specific than just an odor. When an onion is cut into, it opens up onion cells. Along with the opening of onion cells, the enzymes inside of them are released. The enzymes change other substances that have escaped from the open onion cell. Amino acid sulfoxides (which escape), form sulfenic acids. The sulfenic acids put themselves together into a volatile gas.
The volatile gas travels up to the human eye and the gas irritates the eye. Then, the brain sends a message to the eye, telling it water in order to get out the gas. The eye then waters in an attempt to rid itself of the irritation. Thus making a human “cry”
There are certain tactics used in an attempt to avoid the crying. One tactic is to freeze the onion for ten minutes before cutting into it. Another is to cut the onion under water. Another tactic is to chew mint gum.
The conclusion of this project was simple. Onions do make people cry, but the reasoning is not as simple as one may think.


external image cutting-onion.jpg external image Tear.jpg